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Fri, 1 Dec 2017 23:28:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1512170911; bh=jReswuCp7nU9Vh6v6ll+io7pQ4Q06r4qKU55fpwzl8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ktZ5H5IJryaotuYevHWXPJt/Ug3rwn7Swi6qyBGrH4YkF3+EpSybIS9dy+Eakt/2i iC+bMJyo6fsH1SCnVIR8SUuJ4JxNr+adAfZtn737CKvYBuZC5nfcQbmWEW8b6i02U5 cwVw3DRYUnT6+xYGAtDOwP5DBMTEW+bYJZve4z3U= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 53F6B607F5 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=timur@codeaurora.org From: Timur Tabi To: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org, Linus Walleij , Andy Shevchenko , Mika Westerberg , thierry.reding@gmail.com, Stephen Boyd , david.brown@linaro.org, andy.gross@linaro.org, Bjorn Andersson , Varadarajan Narayanan , Archit Taneja Subject: [PATCH 2/4] [v2] gpiolib: add bitmask for valid GPIO lines Date: Fri, 1 Dec 2017 17:28:22 -0600 Message-Id: <1512170904-4749-3-git-send-email-timur@codeaurora.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1512170904-4749-1-git-send-email-timur@codeaurora.org> References: <1512170904-4749-1-git-send-email-timur@codeaurora.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171201_152850_340896_8385765E X-CRM114-Status: GOOD ( 16.41 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: timur@codeaurora.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Add support for specifying that some GPIOs within a range are unavailable. Some systems have a sparse list of GPIOs, where a range of GPIOs is specified (usually 0 to n-1), but some subset within that range is absent or unavailable for whatever reason. To support this, allow drivers to specify a bitmask of GPIOs that are present or absent. Gpiolib will then block access to those that are absent. Signed-off-by: Timur Tabi --- drivers/gpio/gpiolib.c | 47 ++++++++++++++++++++++++++++++++++++++++++++- include/linux/gpio/driver.h | 3 +++ 2 files changed, 49 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 168dd831551d..2c71e8db95a3 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -191,6 +191,28 @@ static int gpiochip_find_base(int ngpio) } } +static int gpiochip_init_valid_mask(struct gpio_chip *chip) +{ + if (!chip->need_valid_mask) + return 0; + + chip->valid_mask = kmalloc_array(BITS_TO_LONGS(chip->ngpio), + sizeof(long), GFP_KERNEL); + if (!chip->valid_mask) + return -ENOMEM; + + /* Assume by default all GPIOs are valid */ + bitmap_fill(chip->valid_mask, chip->ngpio); + + return 0; +} + +static void gpiochip_remove_valid_mask(struct gpio_chip *chip) +{ + kfree(chip->valid_mask); + chip->valid_mask = NULL; +} + /** * gpiod_get_direction - return the current direction of a GPIO * @desc: GPIO to get the direction of @@ -1225,10 +1247,14 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data, if (status) goto err_remove_from_list; - status = gpiochip_irqchip_init_valid_mask(chip); + status = gpiochip_init_valid_mask(chip); if (status) goto err_remove_from_list; + status = gpiochip_irqchip_init_valid_mask(chip); + if (status) + goto err_remove_valid_mask; + status = gpiochip_add_irqchip(chip, key); if (status) goto err_remove_chip; @@ -1259,6 +1285,8 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data, gpiochip_free_hogs(chip); of_gpiochip_remove(chip); gpiochip_irqchip_free_valid_mask(chip); +err_remove_valid_mask: + gpiochip_remove_valid_mask(chip); err_remove_from_list: spin_lock_irqsave(&gpio_lock, flags); list_del(&gdev->list); @@ -1311,6 +1339,7 @@ void gpiochip_remove(struct gpio_chip *chip) /* Numb the device, cancelling all outstanding operations */ gdev->chip = NULL; gpiochip_irqchip_remove(chip); + gpiochip_remove_valid_mask(chip); acpi_gpiochip_remove(chip); gpiochip_remove_pin_ranges(chip); of_gpiochip_remove(chip); @@ -1500,6 +1529,18 @@ static bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gpiochip, return test_bit(offset, gpiochip->irq.valid_mask); } +static bool gpiochip_available(const struct gpio_chip *gpiochip, + unsigned int offset) +{ + pr_info("%s:%u offset=%u\n", __func__, __LINE__, offset); + + /* No mask means all valid */ + if (likely(!gpiochip->valid_mask)) + return true; + + return test_bit(offset, gpiochip->valid_mask); +} + /** * gpiochip_set_cascaded_irqchip() - connects a cascaded irqchip to a gpiochip * @gpiochip: the gpiochip to set the irqchip chain to @@ -3597,6 +3638,10 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev, return desc; } + /* Check if the GPIO line itself is valid */ + if (!gpiochip_available(desc->gdev->chip, idx)) + return ERR_PTR(-EACCES); + status = gpiod_request(desc, con_id); if (status < 0) return ERR_PTR(status); diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 55e672592fa9..b68450caf554 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -316,6 +316,9 @@ struct gpio_chip { int (*of_xlate)(struct gpio_chip *gc, const struct of_phandle_args *gpiospec, u32 *flags); #endif + + bool need_valid_mask; + unsigned long *valid_mask; }; extern const char *gpiochip_is_requested(struct gpio_chip *chip,